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+--- Thread: White pixels left... (/Thread-White-pixels-left)
White pixels left... - Sylus - 11-17-2019
Whenever I select text (alpha channel selection) I get those left over white pixels ... Can someone help me? Did I set anything wrong?
RE: White pixels left... - Ofnuts - 11-17-2019
Where are they? The top of the bevel?
RE: White pixels left... - Sylus - 11-17-2019
(11-17-2019, 09:22 PM)Ofnuts Wrote: Where are they? The top of the bevel?When you zoom in on the letter 'C' you can find them on the left...
RE: White pixels left... - Ofnuts - 11-17-2019
This?
[attachment=3456]
RE: White pixels left... - Sylus - 11-24-2019
(11-17-2019, 10:22 PM)Ofnuts Wrote: This?
yes
RE: White pixels left... - rich2005 - 11-24-2019
It will be something simple in your workflow. Do you still have the Gimp xcf with layers?
A quick remake, not trying to copy, might look like this with layers: https://i.imgur.com/jVNTfkn.jpg
All done with alpha-to-selection from the text layer, but there are semi-transparent (anti-aliased) pixels on the boundaries. Either have them for smoothness or suffer a jaggy edge.
[attachment=3489]
If you do not have the original then I would dive in at a pixel level and paint in some repairs.
RE: White pixels left... - Ofnuts - 11-26-2019
Just a wikd guess: you are likely painting things on the same layer. Along the boundaries of the selection there are partially selected pixels (this is necessary for smoothness). You bucket fill the selection and fill one side: these partially selected pixels are partially painted. Then you invert the selection and paint the other side: these partially selected pixels remain partially selected (100%-partial selection is another partial selection) and so are also partially painted. And partial paint over partial paint is not fully opaque so you get the initial layer showing (or partially transparent pixels letting the layer below show through).
An example of what you would get with a 45° diagonal selection:
[attachment=3503]
If you look closely, the pale squares have a blue component, that cannot be a blend of the pure red and pure green: this is the original white background which is not fully painted over.
This can be averted by growing the selection used in the first fill, so that the second fill's partially painted pixels overlay fully painted pixels from the first fill, namely:
- Create selection
- Select>Save to channel
- Select>Grow
- Fill green
- Restore selection from channel
- Select>Invert
- Bucket-fill with red
[attachment=3504]
In the result, the transition pixels only contain red and green (and are a bit darker)
But in practice, you paint colors on different layers, and a square cut in half along a diagonal would be painted like this using two layers:
[attachment=3505]
This produces exactly the same visual result as the previous solution, while requiring a lot less fiddlin,g woith selections.